Hydraulic valve lifter



June 1969 R. F. ABELL, JR v 3,448,730

HYDRAULIC VALVE LIFTER Filed June 7, 1967 ZZL 55.94 a

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June 10, 1969 Filed June 7, 1967 R. r-'. ABELL, JR HYDRAULIC VALVE LIFTER Sheet 3 of2 A ay A ,45LL, (/2

BY WWW/724 INVENTOR United States Patent 3,448,730 HYDRAULIC VALVE LIFIER Roy F. Abell, Jr., Saginaw, Mich., assignor to Eaton Yale & Towne Inc., Cleveland, Ohio, a corporation of Ohio Filed June 7, 1967, Ser. No. 644,191 Int. Cl. F011 1/24 US. Cl. 123-90 22 Claims ABSTRACT OF THE DISCLOSURE The problem The invention has particular application to the lubrication of the valve gear of internal combustion engines wherein cylinder-head mounted valves are opened by associated push rods and valve rockers; and, using hydraulic lifters between the camshaft and the ends of the push rods. The purpose is to supply oil from the oil gallery, or main oil supply, produced by engine oil pump pressures, to the lifters, for lifter purposes; and then, additionally, have the lifters separately meter oil for lubricating purposes up through the stems of the hollow push rods to the rocker arms, which require adequate lubrication for long life. In the prior art, it has been customary to lubricate the rocker arms from the engine lubricating pump by means separate from the lifters and push rods. As the art has advanced, however, this separate oil supply means has been eliminated by incorporating the lubricating oil feed function into the lifters and moving the oil up through the hollow push rods.

A problem has arisen, however, in prior hydraulic lifters which have attempted to perform this dual function. Notably, they either provide an oversupply of lubricating oil to the rocker arms at high engine operating speeds with consequent loss through the valve guides to the engine cylinders; or else, they are unable to satisfactorily maintain minimum oil delivery requirements at low speeds when measures are taken to prevent oversupply at high speeds.

For example, one typical mchanism of the prior art requires 7 /z minutes after starting the engine to establish oil flow to the rockers using SAE 20W oil at 80 F. Further, in this prior mechanism, a check valve element remains substantially closed up through an engine speed of approximately 1600 r.p.m. These figures clearly bear out the fact that the prior structures are unable to satisfactorily maintain minimum oil delivery requirements at low speeds when measures are taken to prevent oversupply at high speeds.

It is, therefore, an important object of this invention to provide an improved hydraulic lifter for use in rocker lubricating systems.

A further object is to provide an improved hydraulic valve lifter for use in valve rocker lubricating systems in which novel positive metering means are incorporated to insure proper oil delivery rates to the rocker arms throughout the entire operating speed range of the engine.

My invention provides a substantial contribution to the art of combination hydraulic litter and lubricating oil metering devices by providing an improved, simplified, more accurate and trouble-free system wherein check valve devices are eliminated. Further, by the present invention, oil metering is provided in hydraulic lifters by the use of a novel constant length metering land so 3,448,730 Patented June 10, 1969 that oil flow is always proportioned to the lubrication requirements of the engine as dictated by the operating speed of the engine. Also, resistance to clogging is provided by the relative rotation inherent between the socket and the body of the lifter. Further, because of the few parts involvd, there is a high degree of durability inherent in the structure. Few parts contribute substantially to ease of manufacture.

FIGURE 1 is an axial-sectional view of a first embodiment of the combination hydraulic litter and lubricating oil metering device of the present invention wherein the plunger and socket are a one-piece unit;

FIGURE la is a schematic representation of the travel of passage 84 with respect to the groove 48 and the land 50.

FIGURE 2 is a side-elevational view, partly in axial section, of a second embodiment of the invention, similar to the embodiment of FIGURE 1, but wherein the socket is not integral with the plunger.

FIGURE 3 is a side-elevational view, partly in axial section, of a third embodiment of the invention wherein the plunger and socket are separate element-s and wherein part of the oil reservoir is formed in the socket; as distinguished from FIGURE 2, wherein the entire oil reservoir is located in the plunger;

FIGURE 4 is a sectional view, similar to FIGURE 3, but illustrating lands formed respectively on the socket and on the interior of the body in accordance with the prior art; and, showing the plunger in a relatively de pressed position, thereby illustrating the manner in which the length of the control land has been reduced, which in turn accelerates the flow of oil to the valve gear in an undesired fashion; thus, illustrating the problem which has been solved by the invention;

FIGURE 5 is an elevational view, partly in axial section, similar to FIGURE 2, of a lifter of the invention having a two-piece plunger and socket, but with the oil distribution groove of the plunger staggered downwardly relative to the oil distribution groove of the bore of the body in order to provide a greater distribution of oil over the wall area of the bore;

FIGURE 6 is a side-elevational view, partly broken away in axial section, of a further embodiment of the invention, also utilizing a two-piece plunger and socket with part of the oil reservoir chamber being located in the socket, as in FIGURE 3, but further comprising an inversion of the invention in that the constant length metering land is formed on the exterior surface of the socket, as distinguished from being carried by the bore as in the previous embodiments; and, further using an O- ring seal at the socket;

FIGURE 7 is a side-elevational view, partly broken away in axial section, of another embodiment of the invention, where all of the incoming oil moves up to the constant length metering land and then into the plunger reservoir by means of ports provided in the bottom surface of the socket;

FIGURE 8 is a sectional view, taken along the line 88 of FIGURE 7; and

FIGURE 9 is a view, partly in section, showing a portion of an internal combustion engine and using the lifter of this invention.

Referring now more specifically to the drawings, and more especially to FIGURE 1, the reference numeral 20 broadly designates the novel hydraulic valve lifting and oil metering device of the present invention. The lifter 20 comprises a generally cup-shaped body 22 having an annular side wall 24 with a cylindrical outer surface 26. A recessed oil-receiving groove 28 is formed into the cylindrical outer surface 26 in the median portion of the surface. One end of the body 22 is closed by means of a transverse head 30 and the other end 32 is 3 open. In operation, the head 30 bears against the cam of a camshaft in a known manner in present day engine construction.

The interior of the body 22 is formed as a stepped bore 34 that has its largest diameter 36 at the open end; its next largest diameter 38 along the median portion; and, its smallest diameter 40 at the head end. A shoulder 41 limits the downward movement of the plunger '2. Medially, of the next largest diameter 38, there is "a formed an oil distribution groove 42 that falls within the axial limits of the outer oil receiving groove 28. A radial oil supply hole 44 extends through the side wall 24 thereby connecting the grooves 28 and 42. This system, comprising oil receiving groove 28, oil supply hole 44 and oil distribution groove 42, provides the main oil supply into the unit from an appropriate oil gallery passage indicated schematically as 46. An oil pump and a sump, conventional in the art, supply the oil for the oil gallery 46.

Spaced from the internal oil distribution groove 42, there is a collector groove 48, formed in the bore 38 of the body 22. This catches lubrication oil for the rocker arm lubrication, as will be described later.

Between the oil distribution groove 42 and the collector groove 48, there is a fixed length land 50 whose function is very important to the present invention and which will be made clear after the description of the movable control plunger, designated generally as 52, is completed.

In this embodiment of the invention, the plunger 52 is made in one piece and is slidable within the central portion of the body 22, having the diameter 38. A groove 37 is formed within the largest diameter 36 and receives a snap ring 37a which holds the plunger 52 in its operating location within the body 22. The plunger 52 is of cylindrical configuration and the outer surface has two carefully controlled diameters. The head end diameter 54 is quite close, having a clearance on the order of .0002 to .0003 inch less than the diameter 38. This permits the lifter to leak-down in a precise manner, as will be explained.

The clearance between the fixed length land 50 is substantially greater, on the order of .0012 to .0022 inch. It will observed that this difference in magnitude is on the order of ten times greater than the leak-down clearance. This larger clearance permits lubricating oil to pass to the oil collector groove 48 in a metered manner. The upper socket diameter 56 is also of the same order of magnitude as the fixed length land diameter 50, namely, .0012 to .0022 inch less than the diameter of the bore 38 of the body 22. It will be appreciated that the clearance between upper socket diameter 56 and the body may vary.

The head end of the plunger 52 has a shoulder 60 that is further stepped down to an annular valve seat 62 that surrounds a port 64.

The head portion of the plunger 52 is provided with a hollow reservoir chamber 66 that extends between the port 64 and the oil inlet supply hole 44. A radial inlet 68 is provided within the bounds of an oil receiving groove 70 formed around the outside of the plunger. This reservoir chamber 66 holds a supply of oil above the port 64 for supplying lifter function oil.

A pressure chamber 72 is provided between the head end of the plunger 52 and the transverse head 30 of the body 22. A cup-like stamped metal retainer 74 has a radial flange 76 at one end which is seated on the shoulder 60 of the plunger 52 by means of a compression spring 78 that abuts the transverse head 30. The retainer 74 is bent up, as a pair of spring tangs 80, to bias a check valve washer element 82 against the annular seat 62. This provides a check valve against flow of oil from the pressure chamber 72 back into reservoir chamber 66, but permits a free flow of oil through the port 64 and into the pressure chamber 72, as necessary. The spring tangs 80 also limit the distance to which the check valve washer element 82 may move in opening the port 64. The check valve illustrated is for purposes of de scription only. Other check valves known to those skilled in the art may be utilized.

As known to those skilled in the art, during each valve lifter stroke, i.e., as produced by upward movement of the hydraulic lifter 20, oil is trapped in pressure chamber 72 by the closing of the check valve washer element 82 against the seat 62 and the plunger 52 is forced to travel upwardly with the body 22. During each such cam lifting and valve opening stroke, a small amount of the oil trapped in the pressure chamber 72 escapes around the plunger 52, which leakage is termed leakdown and is necessary in order to insure that the engine poppet valve will fully seat on the subsequent return stroke. The subsequent return stroke occurs with the con tinued rotation of the cam, against which the transverse head 30 ridesto provide actuation of the valve gear. Were it not for this leak-down and, if any of the parts of the valve train lengthened due to increase in engine temperature, such greater length would hold the valve slightly off its seat. This would result in valve burning and engine malfunction.

After the valve returns to its seat, the spring 78 continues to maintain the plunger 52 in contact with the lower end of the push rod 58, as illustrated in FIGURE 1, and the body 22 is maintained in contact with the cam surface, meaning positive contact between the transverse head 30 and the cam surface; this takes all lash out of the system. While the lifter 20 is regaining its engagement with the base circle of the cam (not shown, but well-known to those skilled in the art), the plunger 521s therefore moved outwardly of the body 22 'by spring 78 to compensate for leak-down movement of the plunger inwardly on the valve lift stroke. This results in re-enlarging the pressure chamber 72 and permits oil to flow past the then opened check valve washer element 82 from the reservoir chamber 66.

In order to keep the reservoir chamber 66 full, oil is continuously supplied at engine pump pressure from the oil gallery, as indicated by the arrow 46. This oil passes in through the oil distribution groove 42, oil receiving groove 70* and through the inlet 68 to the reservoir 66.

The lubricating oil metering mechanism The top end or socket of the plunger 52 is provided with a transverse passage 84 which intersects an axial passage 86. The transverse passage 84 is always in at least partial overlapping engagement with the collector groove 48 during operation of the hydraulic lifter and is, therefore, of such a width as to provide uninterrupted overlap. The axial passage 86 opens into the bottom of a hemispherical socket 88 which receives the hemispherical end of the hollow push rod 58. The hollow push rod 58 has an opening 90 in the bottom end that lies over the axial passage 86.

During operation, while the lifter 20 is reciprocating to open and close its engine valve and with the reservoir chamber 66 and the oil receiving groove 70 maintained full of oil under pump pressure from the oil gallery, arrow 46, the clearance between the constant length land 50 functions to carefully and accurately meter oil to the collector groove 48. From the groove 48, the oil flows into the passage 84 and then up through the passage 86 and on up the center of the hollow push rod 58 to lubricate the rocker.

Due to the nature of the constant length land 50, a metering of the lubricating oil is produced that is proportional to engine speed on a substantially straight line basis. Thus, the greater the speed of the engine, the greater the need for lubrication and the greater the amount of lubricating oil supplied. The length of the metering land 50 and the clearance between the constant length land 50 and the body 22 may be co-varied for a specific engine to produce proper lubrication for the rocker at all operating speeds.

Note that the length and area of land 50 always remains constant. Thus, in FIGURE 1, the upper position of the plunger 52 places the upper edge of the oil receiving groove 70 in alignment with or below the bottom edge of the land 50. Also, the passage 84 is located above the level where maximum depression of the plunger 52 would cause the passage 84 to be positioned out of communication with collector groove 48.

FIGURE 1a illustrates the extreme positions which the passage 84 may assume and still maintain a constant length metering land 50. In the upper position of the socket, the passage 84 just overlaps the upper edge of the wall defining the collector groove 48. In the upper position of the socket the flow of oil is across the metering land 50, into the collector groove 48 and therefore into the passage 84. In the bottom position of the socket, the passage 84 just overlaps the bottom edge of the wall defining the groove 48. Most of the oil, as indicated by arrows a of FIGURE 1a, will be metered across the constant length land 50. Some oil, as indicated by arrow b, will travel a distance less than the length of the land 50. This oil, however, is quite localized in that the passage 84 comprises a small part of the circumference of the wall defining the land 50. Therefore, essentially constant length metering is achieved with the socket in the bottom position and the passage 84 positioned as shown in FIG- URE 1a. The positions of passage 84 as shown in FIG- URE 1a, are for purposes of illustrating the extremes in travel of the plunger in order to maintain constant length land metering of oil. It is not necessary that the plunger assume these extreme positions. It is merely necessary that communication between the passage 84 and groove 48 be uninterrupted during travel of the socket.

It will be clearly evident from the foregoing that the number of parts has been significantly reduced as compared to the multi-piece units of the last ten years of the prior art. In fact, it will be evident that there are no moving parts other than the plunger 52 and the housing 22 which make up the lifter 20, as regards lubrication oil supply at the socket end of the unit. This is a substantial and significant advancement to the art and provides oil metering of an accuracy that has not heretofore been obtainable.

This invention, therefore, provides a substantial improvement over prior structures where starvation at lower engine speeds resulted from efforts taken to prevent oversupply at high speeds.

The embodiment 0) FIGURE 2 This embodiment of the invention is similar to the embodiment of FIGURE 1, but the plunger 92 is a twopiece unit for greater ease of manufacture and for greater economy of manufacture.

Thus, the body 22 is the same, with the snap ring 37a to hold the plunger 92 in its operating position. Note particularly, the retained presence of the constant length flow metering land 50, being defined on the interior 38 of the body 22 by means of the oil distribution groove 42 and the oil collector groove 48.

The head section 94 of the plunger 92 is generally the same as the head end of the plunger 52 of FIGURE 1, and terminates at the upper end at the parting line 96- It will be evident in this embodiment, that it is much easier to machine the reservoir chamber 98 because of tool access from each end. The socket 100 it analogous to the socket end of the plunger 52 of FIGURE 1. However, the inlet 102 is out along the bottom of the socket 100 as compared to the inlet hole 68, according to the embodiment of FIGURE 1.

Therefore, this embodiment of the invention illustrates further that the constant length metering land can be embodied in varied forms of the invention.

This embodiment operates the same as FIGURE 1, relative to lubricating oil passing the constant length metering land 50, then following the transverse passage The embodiment of FIGURE 3 This embodiment of the invention is similar to the embodiment of FIGURE 2 by utilizing a two-piece plunger and socket 104. Part of the oil reservoir 106 is formed in the socket 108, as distinguished from the embodiment of FIGURE 2, wherein the entire oil reservoir is located in the plunger.

In the present embodiment, again the constant length metering land 50 is employed, being defined on the bore 38 of the body 22 by means of the oil distribution groove 42 and the oil collector groove 48. The snap ring 37a i retained to hold the plunger and Socket 104 within its operating limits in the bore 38.

The plunger and socket 104 comprise a plunger section 110 which is generally the same as in FIGURE 1 as regards the check valve details. This terminates at the upper end at the parting line 112. The larger portion 114 of the oil reservoir 106 is formed in the plunger section 110 by means of a straight bore 116. This embodiment has substantial ease of machining due to ready tool access to each end of the head section 110.

The socket 108 is analogous to the socket of FIGURE 2. However, a smaller section 118 of the oil reservoir 106 is formed in the socket 108 by means of a blind hole 119. Also, the inlet 120 is cut across the bottom the entire length of the diameter as in FIGURE 2.

This embodiment goes, however, a step further in providing an oil collector groove 122 around the socket 108. The length and area of the metering land 50 will always remain constant during the operation of the lifter.

Again, this embodiment of the invention still further illustrates that the constant length metering land 50 can be embodied in varied forms of the invention.

This embodiment of the invention operates the same as FIGURES 1 and 2 relative to lubricating oil passing the constant length metering land 50, and then following the transverse passage 124 to the axial passage 86 and then up the push rod 58. The advantages of machining ease are readily apparent.

Comparison of these three embodiments to the prior art variable length metering land of FIGURE 4 While FIGURE 4 is not a copy of any of the prior art, it is nevertheless an embodiment of the prior art into the environment of the present, invention for purposes of accurately comparing the dilferences between the prior art and the constant length metering land of the invention.

The body 126 is generally the same with exception that the collector groove 48, as in FIGURE 1, 2 and 3, is omitted. Therefore, no constant length metering land is present in this typified prior art. The oil collector groove 122 on the plunger 128 will be positioned at various locations relative to the oil distribution groove 42 depending on the lash setting of the lifter.

This produces a variable length land; as indicated by the legend, based upon the lash setting.

Thus, FIGURE 4 vividly points up the eifectiveness of the constant length land of the invention as shown in FIGURES 1, 2, and 3, in metering oil accurately to the rockers via the hollow push rods 58 under all conditions of engine operation.

Thus, by the present invention, at low speeds an adequate amount of oil for lubricating the rockers is provided which overcomes the starvation conditions inherent in structures of the prior art, where measures, such as complicated check valves, are taken to prevent oversupply at high speeds.

Further, by the present invention, at higher engine speeds, the supply of oil is adequate, but controlled to avoid excess. Thus, as engine speeds increase, there is a corresponding lineal increase in lubricating oil flow. However, the constant length metering land of the present 7 invention prevents the flooding. This, therefore, is a substantial improvement over the lifter of FIGURE 4.

The present invention provides all of the improved features in a novel but very simple Way using the constant length land metering control concept and, at the same time, greatly reduces the number of parts in the mechanism as contrasted to the prior art.

The embodiment of FIGURE This embodiment of the invention is similar to the embodiment of FIGURE 2 by utilizing a two-piece plunger and socket 130, with the oil reservoir 132 formed in the plunger 134. Thus, the body 22 of the litter is the same, with the snap ring 37a retained to hold the plunger and socket 130 within its proper operating limits in the body 22. Note particularly the retained presence of the constant area metering land 50, being defined on the interior 38 of the body 22 by means of the oil distributing groove 42 and the collector groove 48.

The bottom end of the plunger 134 is generally the same as the bottom end in FIGURE 1, as regards the check 'valve mechanism. The head section 134 terminates at the top at the parting line 136. The oil reservoir 132 is formed in the plunger 134 by means of a straight bore 138. This embodiment presents substantial ease of machining the bore 138 and the check valve seat 62 due to the tool access to each end of the plunger 134.

The socket 140 is analogous to FIGURE 2 with the inlet 142 extending across the bottom the entire length of the diameter.

It will be noted that the oil receiving groove 144 is formed principally at the upper end of the plunger 134 and is thereby staggered downwardly relative to the oil distribution groove 42 of the body. This provides greater oil mass distribution along the exterior of the plunger and socket 130 in the area surrounding the transverse inlet 142 for improved feed, both to the constant length land 50 for lubricating oil purposes upwardly, and also for filling the reservoir 132 through the transverse inlet 142. This facilitates flow of oil from the gallery 46 into the oil reservoir 132.

Again, this embodiment of the invention illustrates further that the constant length metering land 50 concept can be embodied in various forms of the invention.

This embodiment operates the same as the others in metering lubricating oil past the constant length metering land 50, then following the transverse passage 84 to the axial passage 86 and thence up the push rod 58 to the rocker arm.

The embodiment 0 FIGURE 6 This embodiment illustrates an inversion of the invention. Thus, the constant length metering land 146 is formed on the exterior of the plunger 152, as distinguished from the inner surface or bore of the body 154, as in the previous embodiments. Actually, the constant length land 146 is formed between an annular groove 1 83 and groove 150. By using the O-ring seal 156 at the upper end of the socket 158, the top end of the socket can be ground to a single diameter, rather than requiring two diameters, one for metering and one for a relative seal, as may be encountered in certain instances when using the embodiments of FIGURES 1, 2, 3 and 5.

In the present embodiment, the oil distribution groove 160 has the upper edge in alignment with the upper limit of the oil supply hole 162, formed through the body 154. Also, the body 154 has a groove 164 formed adjacent to the open end to accept the O-ring seal 156.

The snap ring 37a is retained to hold the plunger 152 within its operating limits within the bore 166 of the body.

The plunger and socket 152 is a two-piece unit for greater ease and economy of manufacture. This includes a plunger 168 which is generally the same as FIGURE 1 as regards to check valve details. The plunger 168 terminates at the upper end at the parting line 170'. The large 8 portion 171 of the oil reservoir 172 is formed in the plunger 168 by means of a straight bore 174. This pro vides subtantial ease of machining due to the tool access at each end of the plunger 168.

The socket 158, is analogous to FIGURE 3 with the inlet 176 extending the entire length of the diameter across the bottom face, e.g., at the parting line 170.

The oil receiving groove is formed around the upper end of the plunger 168 and terminates at the top of the transverse inlet passage 176. Thus, the inlet 176 intersects the lower oil receiving groove 150.

The smaller section 178- of the oil reservoir 172 is formed into the socket 158 by means of a blind hole 180.

It will be noted that the constant length metering land 146 is, therefore, formed on the socket 158 between the annular groove 183 and the lower groove 150.

Since the extreme lower position of the plunger and socket 152, as illustrated, places the top edge of the grooves 150 and 160 in alignment, the constant length of the metering land 146 is never diminished. When the plunger 152 is high, the metering land 146 is always opposed to continuous wall area of the bore 166.

Again, this embodiment of the invention illustrates further that the constant length metering land 146 concept can be embodied in various forms of the invention.

This embodiment operates the same in metering the lubricating oil past the constant length metering land 146, then following the transverse passage 182 to the axial passage 86 and thence up the push rod 58.

The embodiment of FIGURES 7 and 8 This embodiment includes several of the features of the previously described embodiments. Further, this is an inversion of the invention, as in FIGURE 6, in that the constant length metering land 184 is formed between two spaced grooves 186 and 188 carried on the exterior surface of the socket 242.

In this embodiment, the body 192 has a cylindrical outer surface with oil-receiving groove means 28 in the median portion thereof. One end is closed by means of a head 30 and the other end is open.

The interior of the body 192 is formed as a stepped bore that has its largest diameter 194 at the open end; its next largest diameter 196 along the median portion; and, its smallest diameter 198 at the bottom. A shoulder 200 limits the downward movement of the plunger Medially of the central bore diameter 196, there is an oil distribution groove 204 that falls within the axial limits of the external oil receiving groove 28. A radial oil supply hole 208 connects the grooves 204 and 28 to provide oil from the gallery, as indicated at 46.

A snap ring 37a in a groove 210 holds the plunger 190 within the body 192 against the compression spring 212 at the bottom.

The plunger 214 and socket 242 are made in two pieces which slide as a unit within the central bore diameter 196. The plunger 214 terminates at the upper end at the parting line 216. At the bottom is a shoulder 218 that is further stepped down to a valve seat 220 that surrounds a port 222. The oil reservoir chamber 224 is formed com pletely within the head section 214 as a stepped bore 226 connecting with the port 222. The oil reservoir chamber 224 extends from the port 222 to the parting line 216. An oil receiving groove 230 is provided on the outside of the plunger 214-The oil receiving groove 230' is oriented to overlap the oil distribution groove 204 on the bore 196.

A pressure chamber 232 is provided between the bottom of the plunger 214 and the head 30. A stamped metal cup retainer 234, as in FIGURE 1, has the radial flange 236 positioned against the shoulder 218 of the plunger 214. The compression spring 212 abuts the radial flange 236 and the head 30 to hold the metal cup retainer 234 in place and also to bias the plunger 214 outwardly of the body 192. The spring tangs 238 bias the check valve washer element 240 against the annular seat 220- to func- 9 tion as described in FIGURE 1 as a check valve mechamsm.

The socket 242 extends upwardly from the parting line 216. The oil inlet 244 comprises intersecting passages 246 cut across the bottom, the entire length of the diameter of the socket 242, see FIGURE 8. A chamfer 248 around the bottom defines the bottom of the constant area metering land 1-84. This functions to produce a groove previously referred to as 188, see FIGURE 7, left side.

The constant length metering land 184 extends from the chamfer 248 (oil receiving groove 244) to the annular oil collecting groove 186. A transverse passage 252 communicates with groove 186 and intersects an axial passage 254 that opens into the bottom of the hemispherical socket 256 that receives the lower end of a push rod.

The lifter functions for lifting purposes at the bottom end of this embodiment in the same manner as previously described.

However, the oil for lubrication purposes is carefully distributed all around the bottom of the socket 242 through the intersecting passages 246, FIGURE 8, .and the chamfer 248, making the groove 188 and thus the inlet 244.

The constant metering land 1'84 functions to carefully and accurately meter oil to the collector groove 186 where it flows via passages 252 and 254 to the socket 256 and then the push rod and thence to the rocker. Note that the constant length metering land 184 always remains constant. Thus, in FIGURE 7, the plunger 190 is bottomed and the chamfer 248 (oil inlet 244) is above the upper limit of the oil distributing groove 204.

It will be evident that all features of the invention are preserved in this embodiment. Further, parts have been reduced to a minimum and ease of machining and economy of manufacture are at once apparent. Also, there are no moving parts except the movement of the plunger 214 relative to the body 192 and movement of the socket 242 relative to the body 192.

The use environment of the invention FIGURE 9 illustrates a portion of an engine which includes a cylinder block 258 in which cylinders 260 are provided. The cylinders 260 are closed at the upper end by a cylinder head 262. Within the cylinder block 2 58 there is journaled a camshaft 264 having cams 266. Adjacent to each cam 266 there is provided in the cylinder block 258 a bore 268 in which is slidably arranged a hydraulic lifter 20' of this invention. Operable engagement between the rotatable cam 266 and the lifter 20 causes it to reciprocate in the bore 268.

The cylinder block 258 is provided with an oil conduit system 259, comprising part of the oil gallery indicated at '46 in the previous figures of the drawings. This oil conduit system 259 communicates with the bores 268. It will be observed that the oil receiving groove 28 of the lifter 20 is in positive communication with the oil conduit system 259. The lifter 20 thereby receives oil in the manner hereinabove described, as via the radial port 44, FIGURE 1.

A poppet valve 270 is mounted for reciprocation in thecylinder head 262 and is biased to a closed position by a compression spring 272. The valve 270 is operably connected to the lifter 20 by means of a rocker 274 and the hollow push rod 58.

The particular valve rocker 274 illustrated is made in the form of a generally channel-shaped sheet metal stamping or casting having downwardly presenting end surfaces 276 and 278 which are in bearing engagement with the upper end of the valve 270 and the upper end of the push rod 58, respectively. The intermediate portion is formed as an upwardly presenting bearing surface 280 which is journaled for pivoting movement on a bearing member 282 fixed to the cylinder head 262 by means of a stud 284 and a capturing nut 286. The bearing surface 280 includes pivoting means to receive the bearing member 282. The end surface 278 is hemispherically concave to receive the hemispherically convex upper end of the hollow push rod 58. Both the upper end of the push rod 58 and the end surface 278 of the rocker are provided with small oil ports 288 and 290, respectively. The push rod 58 has a sliding fit in a guide way 292. The push rod 58, being thus laterally supported and socketed at its upper end in the rocker 274, serves to rotate the rocker about the axis of the stud 284 to the extent necessary to maintain the rocker in proper bearing engagement with the stem of the valve 270.

The upper end of the hydraulic lifter 20 receives the lower end of the push rod 58 in the manner illustrated in FIGURE '1.

It is the purpose of the invention to provide metered lubricating oil to the rocker 274 as it rocks on its mount 282. The manner in which the lifter 20 meters oil up through the hollow push rod 58 at all engine speeds has been previously described. This metered oil flows through the two ports 288 and 290 and thus lubricates the bearing surface between the upper end of the push rod and the back end 278 of the rocker 274. Some of this oil runs back down the push rod 58 to lubricate it in its guide way 292. The principal part of the oil, however, spills over to the rocker bearing surface 280 and the bearing member 282. The greatest amount of stress and thus the greatest need for lubrication is at this point. This oil then runs over the outer end 276 of the rocker 274 and flows around to lubricate the valve stem-rocker bearing surface 276. Some oil also flows down the valve stem to lubricate it in its guideway. Any excess oil leaking past the valve stem will be lost into the cylinder 260 and burned by the combustion.

In view of this condition existing, that is the requirement for adequate but not surplus lubrication, it is therefore important to make clear at this point the reason why the proper amount of lubricating oil is necessary at all speeds. First, at low speeds, oil is required to lubricate all of the bearing points which have been mentioned in order to prevent scoring and scrubbing at the frictional bearing forces which are involved, and these are substantial. Thus, these parts will wear rapidly if permitted to run dry at low speeds, or an any other speeds.

At high speeds, there must not be so much oil supplied as to cause flooding in the rocker compartment. Oil return passages are, of course, provided in this rocker compartment which circulate the oil back down through the engine block 258 to the crankcase sump and to the oil pump. However, these oil return passages have limited flow capacity and, therefore, flooding can result. As mentioned above, oil traveling down the valve stem is lost to the combustion process. When flooding takes place, excess oil follows down the valve stem and works its way into the cylinder 260 where it is burned. In accordance with the present invention, this is prevented by the accuracy of oil flow.

The valve gear arrangement, as shown in FIGURE 9, is for purposes of illustration only to show the operation of the oil metering structure of applicants valve lifter. Other types of rocker arms and rocker arm pivots are included Within the scope of this invention as applicants invention is suitable generally for lubricatnig valve gear.

By the present invention, positive and accurately metered amounts of oil provide lubrication at low speeds. Further, while providing proper amounts of oil at high speeds, the invention also prevents flooding and consequent loss. A substantial contribution to the art has, therefore, been provided as will be evident by the accuracy and simplicity inherent in the present invention.

Extended scope of invention Within the scope of this invention, the constant length metering land can be made as a smooth surface, and also as a tortious path. The foregoing description has related this constant length metering land as an impliedly smooth surface working against a mating smooth surface. However, it is within the scope of the invention to make either or both the constant length metering land and the surface against which it works as a tortious path. This can be done by fine scoring or by fine knurling. Other means will be evident to the artisan.

It has been described that the spaced grooves defining the constant length metering land can be on either the bore of the body or on the exterior of the plunger. Therefore, the language of the claims is to be construed in this manner by reciting means on One of said bore and exterior of said plunger defining a constant area metering land. Within the scope of the invention, this definition includes spaced grooves, and such grooves can be parallel to one another. Further, the grooves can be parallel and extend circumferentially of one of the exterior of the plunger and the bore. More particularly, the grooves can lie in planes perpendicular to the axes of the bore and plunger.

I claim:

1. A hydraulic valve lifter comprising in combination:

a body member having a generally cylindrical exterior surface and an internal wall defining a generally cylindrical bore extending from an open first end of said body to a closed second end of said body, said body member further including a first passage from said exterior surface to said bore,

plunger means disposed in said bore for reciprocation therein, said plunger means having a generally cylindrical exterior surface and an internal reservoir space, said plunger means further including,

a closed first end defining a seat for a push rod, an open second end in communication with said reservoir space, first groove means on the exterior surface of said plunger means, a second passage from said first groove means of said plunger means to said reservoir space, a third passage means from said cylindrical exterior surface of said plunger means to said seat, means to retain said plunger means in said bore, means between said plunger means and said closed second end of said body to bias said plunger means outwardly of said bore, check valve means between said open second end of said plunger means and said closed second end of said body, second groove means at the interface of said body and said plunger means at least partly overlying said third passage means at all times during reciprocation of said plunger means, third groove means at the interface of said body and said plunger means spaced apart from said second groove means, and means to conduct fluid from said first passage to said third groove means, the interface of said body and said plunger means between said second groove means and said third groove means defining at all operating positions of said plunger means in said bore a constant length surface to restrict and control the flow of fluid from said first passage to said seat.

2. In apparatus of the class described,

a cup-like body having an annular wall that is closed at one end and open at the other end and defining an internal bore,

first port means in said wall, opening into said bore,

for introducing oil into said bore,

a plunger reciprocable in said bore, and means carried by said body and restraining movement of said plunger within said bore,

said plunger having a socket end located adjacent to said open end of said body and a head end located adjacent to the closed end of said body,

an oil reservoir within said plunger, and second port means extending from said reservoir to the exterior 12 of said plunger to conduct oil from said bore into said reservoir, third port means from said reservoir through the head end of said plunger,

means at the head end of said plunger and connected to said third port means and operable with said body, defining check valve means from said reservoir into said bore,

fourth port means in the socket end of said plunger to conduct metered oil from the surface of said plunger through said socket end, and

means on one of said from and exterior of said plunger defining with the interface of said body and plunger,

at all operating positions of said plunger in said bore, a constant length annular metering land located between said first port means and said fourth port means.

3. The invention according to claim 2 wherein said plunger slides in said bore in precisely fitted relationship to Provide leak-down oil flow around said plunger between said head end and said first port means; and, lower pressure oil metering between said first port means and said fourth port means.

4. The invention according to claim 2 wherein said means defining a constant length metering land comprises spaced grooves formed circumferentially on one of said bore of said body and said exterior of said plunger.

5. The invention according to claim 4 wherein said spaced grooves are parallel to one another and lie in planes perpendicular to the axes of said plunger and bore.

6. The invention according to claim 4 wherein said grooves are formed on said bore and are located between said first port means and said fourth port means.

7. The invention according to claim 4 wherein said grooves are formed on the exterior of said plunger and are located between said first port means and said fourth port means. I

8. The invention according to claim 2 wherein the clearance between that portion of the exterior of said plunger from said second port means to said head end, and said bore, is sufiicient for oil leak-down; and, the clearance between the exterior of said plunger and said bore in the area of said constant length metering land is of a magnitude to provide lower pressure oil metering.

9. The invention according to claim 6 wherein the clearance between that portion of the exterior of said plunger from said second port means to said head end, and said bore, is sufficient for oil leak-down; and, the clearance between said metering land formed on said bore, and the exterior of said plunger, is of a magnitude to provide lower pressure oil metering.

10. The invention according to claim 7 wherein the clearance between the exterior of said plunger from said second port means to said head end, and said bore, is sufiicient for oil leak-down; and, the clearance between said metering land formed on the exterior of said plunger, and said bore, is of a magnitude to provide lower pressure oil metering.

11. The invention according to claim 2 wherein said plunger is formed of two sections, a head section and a socket section,

said head section extending from said first port means to said head end,

said oil reservoir being formed within said head section and the third port means extending from said reservoir to the exterior of said plunger through said head end,

said socket section extending from said first port means to said socket end and said second port means being located in said socket section, and

wherein said constant length metering land comprises spaced parallel grooves formed oircumferentially on said bore and are located between said first port means and said fourth port means.

12. The invention according to claim 2 wherein said plunger is formed in two sections, a head section and a 13 socket section, said head section extending from said first port means to said head end,

said oil reservoir formed partly in said head section and the third port means extending from said reservoir to the exterior of said plunger through said head end of said plunger,

said socket section extending from said first port means to said socket end and including part of said reservoir means, and said part being in communication with the part formed in said head section,

said second port means being located in said socket section, and

wherein said constant length metering land comprises spaced parallel grooves formed circumferentially on said bore and are located between said first port means and said fourth port means.

13. The invention according to claim 2 wherein said plunger is formed in two sections, a head section and a socket section, said head section extending from said first port means to said head end,

said oil reservoir being formed in said head section,

and said third port means extending from said reservoir to the exterior of said plunger through said head end of said plunger,

said socket section extending from said first port means to said socket end,

said second port means being formed partly in said socket section and partly on the exterior of said head section, and

wherein said constant length metering land comprises spaced parallel grooves formed circumferentially on said bore and are located between said first port means and said fourth port means.

14. The invention according to claim 2 wherein said plunger is formed in two sections, a head section and a socket section, said head section extending from said first port means to said head end,

said oil reservoir being formed partly in said head section and said third port means extending from said reservoir to the exterior of said plunger through said head end,

said socket section extending from said first port means to said socket end and including part of said reservoir means, and said part being in communication with the part formed in said head section,

said second port means being formed partly in said socket section, partly on the exterior of said socket section, and partly on the exterior of said head section, and all of said ports being in communication, and

wherein said constant length metering land is defined by a groove formed circumferentially on the exterior of said plunger and located between said first port means and said fourth port means.

15. The invention according to claim 14 including seal means between said bore and the exterior of said plunger, located between said fourth port means and that end of said plunger.

16. The invention according to claim 2 wherein said plunger is formed in two sections, a head section and a socket section, said head section extending from said first port means to said head end,

said oil reservoir being formed in said head section and the second port means extending from said reservoir to the exterior of said plunger to communicate with said first port means,

said third port means extending from said reservoir to the exterior of said plunger through said head end of said plunger,

shoulder means in said bore adjacent to said closed end of said body and groove means in said bore adjacent to said shoulder,

said socket section extending from said first port means to said socket and having a top at the open end of said bore and a bottom abutting said lower section, and exposed to said oil reservoir,

fifth port means formed in said socket section as intersecting grooves extending the full diameter across the bottom of said socket section and communicating with first external groove means formed circumferentially around the exterior of said socket section, and wherein said constant length metering land is defined by said first external groove means and a second external groove means on the exterior of said socket section and spaced from said first external groove means, and said second groove means being connected to said fourth port means.

17. The invention according to claim 16 wherein said first port means includes connecting groove means in radial alignment in said bore, and said second port means includes connecting groove means in radial alignment around the exterior of said body, and said respective groove means being in communication with one another.

18. In a lubricating system of the class described, including a hydraulic lifter actuated for reciprocation, the lifter having a plunger reciprocative in a supporting bore,

an oil inlet into said bore and an oil outlet through said plunger, a member externally of said lifter having a bearing surface in fluid communication with said outlet,

means for conducting pressurized oil to said inlet, and

means on one of the exterior of said plunger and said bore defining, at all operating positions of said plunger in said bore, a constant length annular metering land located between said inlet and said outlet.

19. A valve tappet comprising a body member adapted to be reciprocated by a cam member, said body member having a cavity connected in fluid communication with a source of lubricant, and socket means slidably mounted in said body member for engagement with a push-rod member to effect motion of the push-rod member, said socket means having a fluid passageway therein to provide for lubricant flow to the push-rod member, said body member and socket means having metering surfaces thereon which are cooperable to define, at all operating positions of said plunger in said bore, a constant length annular metering passage for controlling the flow of lubricant from the cavity in said body member of said passageway in said-socket means to thereby regulate the flow of lubricant from the source of lubricant to the push-rod.

20. A valve tappet as set forth in claim 19 wherein said metering surfaces comprise an annular internal surface of said body member and an annular peripheral surface of said socket means.

21. A valve tappet as set forth in claim 20 wherein said body member defines a pair of spaced apart and substantially parallel annular grooves which limits the axial extent of said metering surface on said body member.

22. A valve tappet as set forth in claim 20 wherein said socket means includes an annular groove connected in fluid communication with said passageway in said socket means, said annular groove defining one of the axial limits of said metering surface on said socket means.

References Cited UNITED STATES PATENTS 2,865,352 12/ 1958 Thompson. 2,874,685 2/ 1959 Line. 3,124,114 3/1964 Voorhies. 3,322,104 5/1967 Abell.

AL LAWRENCE SMITH, Primary Examiner.

US. Cl. X.R. 

